I have the same type of issue on my webpage as well. It's not the same script as mentioned above, but it does always occur on pages that contain PHP code. I believe the issue stems from the fact that most of our websites are on shared servers, and that it takes it a few moments for the server to process the PHP code, because it's busy doing it for the other 1,000 websites at the same time on that individual box.
Example: Go to my website and click on the "Local with Lightning Detect" under Radar, it should be pretty fast. It is an html only page with images from Wunderground.
Now click on my "Hurricane - Tropic Forecast", it is PHP, and is slow, most likely because of the server's PHP work load from other sites, and perhaps increasingly that the fact is I ask it to display all of the weather information in detail.
You may also noticed that when you first pull up my website, it takes a second or two for the info in the Yellow "Weather Advisory Box" in the upper right corner to update. But again I expect this from my web server, because I am using the cheapest hosting plan that Godaddy has to offer.